Abstract

Kallikrein is present in mammalian plasma as the inactive form, kallikreinogen. The enzymatic activation of kallikreinogen with trypsin and unfractionated serums has first been shown by WERLE et al. (1955). It is also well known that when whole plasma is treated with acid, casein, acetone or glass powders, kallikreinogen is converted to the active enzyme. In addition to these activations of kallikreinogen, MARGOLIS (i960) has suggested that Hageman factor will be required for the endogeneous activation of the kallikreinogen in plasma, and other workers have considered that this activation proceeds via activation of permeability globulin. This idea is mainly based on the observations of RATNOPF and MILES (1964) that permeability globulin could be activated by Hageman factor and that permeability globulin releases kinin from the unfractionated plasma.